Occurrence of treatment-emergent adverse events up to the final study visit (maximum 3 years of study treatment plus 6-month safety follow-up period).

Occurrence of serious adverse events up to the final study visit (maximum 3 years of study treatment plus 6-month safety follow-up period).

Occurrence of adverse events of special interest up to the final study visit (maximum 3 years of study treatment plus 6-month safety follow-up period). Adverse events of special interest include the anticipated risks of treatment with cenerimod, known class effects, and events that may be related to systemic lupus erythematosus comorbidities, i.e., adverse events related to: * Effects on heart rate and rhythm * Hypotension * Hypertension * Cardiovascular * Hepatobiliary disorders / liver enzyme abnormalities * Pulmonary * Eye disorders * Infections * Skin malignancies * Non-skin malignancies

Response on SRI-4 is defined as: * Reduction from baseline of at least 4 points in the modified Systemic Lupus Erythematosus Disease Activity Index-2000 score (mSLEDAI-2K \[SLEDAI-2K modified to exclude leukopenia, thus mSLEDAI-2K\]), and * No new British Isles Lupus Assessment Group-2004 (BILAG) A organ domain score and not more than one new BILAG B organ domain score compared to baseline, and * No worsening from baseline in subjects' lupus disease activity, where worsening is defined as an increase ≥ 0.30 points on a 3-point Physician's Global Assessment visual analog scale (PGA VAS), and * No violation of specified medication rules detailed in the core protocol.